Drafting board attachments

ABSTRACT

The drafting board has a drafting machine provided with a vertical track laterally movable across the board. A protractor support plate is vertically slidably mounted on the vertical track. A protractor head carrying vertical and horizontal scales is mounted on the lower portion of the support plate, the support plate having a narrowed extension track disposed parallel with and spaced from the vertical track, and the extension track having a longitudinally disposed keyway therein. A lamp support base is adjustably mounted on the extension track in way of the keyway. A swingable lamp support tube has one end fixedly mounted on the lamp base, the tube carrying at its other end a reflector carrying a lamp. And a transformer is mounted on the vertical track and connected to a source of electrical power. The transformer having leads extending therefrom and through the lamp support tube to the lamp, whereby the lamp may be fixedly adjusted into close proximity to the protractor head to always illuminate the head while eliminating shadows on the vertical scale as the protractor head is shifted vertically or horizontally across the drafting board.

United States Patent [1 1 Smith 1 3,733,703 51 May 22,1973

[54] DRAFTING BOARD ATTACHMENTS [76] Inventor: Ruth Ann Smith, 22 McArthur Dr.,

Jacksonville, NC 28540 [22] Filed: July 20, 1972 [21] Appl. No.: 273,453

[52] US. Cl. ..33/79 R [51] Int. Cl. ..B43l 13/02 [58] Field of Search ..33/76, 78, 79, 86; 108/23 [56] References Cited FOREIGN PATENTS OR APPLICATIONS 1,169,465 9/1958 France ..33/79 R Primary Examiner-Harry N. Haroian Att0rneyArthur E. Dowel], Jr. and Arthur E. Dowelllll [57] ABSTRACT The drafting board has a drafting machine provided with a vertical track laterally movable across the board. A protractor support plate is vertically slidably mounted on the vertical track. A protractor head carrying vertical and horizontal scales is mounted on the lower portion of the support plate, the support plate having a narrowed extension track disposed parallel with and spaced from the vertical track, and the extension track having a longitudinally disposed keyway therein. A lamp support base is adjustably mounted on the extension track in way of the keyway. A swingable lamp support tube has one end fixedly mounted on the lamp base, the tube carrying at its other end a reflector carrying a lamp. And a transformer is mounted on the vertical track and connected to a source of electrical power. The transformer having leads extending therefrom and through the lamp support tube to the lamp, whereby the lamp may be fixedly adjusted into close proximity to the protractor head to always illuminate the head while eliminating shadows on the vertical scale as the protractor head is shifted vertically or horizontally across the drafting board.

5 Claims, 4 Drawing Figures PATENTED MAY 2 2 I973 SHEET 2 [1F 2 DRAFTING BOARD ATTACHMENTS This invention relates to drafting machines, and the principal object of the invention is to provide certain novel attachments adapted to be attached to the vertical tracks of such drafting boards or machines to insure proper illumination of the drafting board to the vicinity of the work being done thereon by the draftsman, thereby eliminating shadows on both sides of the vertical scale, simultaneously, thereby alleviating cost of overhead lighting, and also eliminating eye-strain and fatigue on the part of the draftsman, thereby"inc're'asing-- the efficiency and speed of the operator, especially those drafting eight hours a day or longer.

Another object of the invention is to provide attachments as above indicated which can be manufactured as a working part of the drafting machine at a moderate cost, or can be manufactured in kit form and adapted to be mounted on drafting. machines now inuse.

The light required for a draftsman is 80 to 100 footcandles, approximately 6 watts per square foot of his drafting board, a requirement which is too often underestimated. If the light could be concentrated on the square foot on which the draftsman is drawing, and acsuitable external wiring as may be required for use in kit form.

In said device the tracking device should be of suitable size, lightweight, and capable of supporting the lamp assembly and allowing the lamp to slide or glide in a vertical motion. The tracking device may be manufactured in one piece with the protractor support plate (located underthe vertical track), or it may be manufactured as an extension to be attached to the existing support plate as a modification, in kit form for older .drafting machines now in use; and its rod or slotted plate should be long enough to enable the lamp bulb to be positioned on the same horizontal centerline as the top of an 18-inch vertical scale for maximum efficiency.

I willexplain the invention with reference to the accompa'nying drawings which illustrate one practical embodiment thereof to enable others familiar with the ,art to adopt and use the same; and will summarize in complished automatically, it would eliminate much time and expense. My present invention was conceived through necessity of eliminating shadows on both sides of the vertical scale simultaneously, and to alleviate costly overhead lighting in any size drafting room. My invention will also relieve undue eyestrain and fatigue on the part of the draftsman and will increase his efficiency and speed, especially where he has been drafting eight hours a day and longer.

According to my invention the device consists of three basic parts, to wit, (1) a high intensity lamp; (2) a transformer; and (3) a tracking device. In said device the lamp is attached to the same movable base plate that supports the customary protractor head, the baseplate being vertically movably mounted on the underside of the vertical track. As the protractor head is moved horizontally and/or vertically, the light automatically remains in the same relative position with respect to the protractor head as well as to both scale, eliminating shadows completely. The lamp can be positioned at any required distance and convenient location; also the lamp may have an On-Off switch conveniently located on the vertical track, on the lamp base, or on the lampshade, which switch may be a three-position Off- Low-I-Iigh" switch; also the neck of the lamp may be of flexible conduit such as the gooseneck cable type, or it may be a two-part rod (wire inside) with three swivel or ball joints so that the lamp may be positioned to virtually any angle from the lamp base, and the neck should be long enough to center the lamp bulb over the centerline of the vertical scale. The lamp base will have a knurled knob or ball type setscrew for positioning the lamp at any point along the tracking device.

In said device the transformer should be of the smallest physical dimensions and of the lightest weight available. It is mounted on the upper end of the vertical track (separated from the lamp) so that there is no excessive weight on the protractor head thus eliminating the need for extra counterbalance weights or brake adjustments on the vertical track. It may be mounted on the upperside of the track or to the right of left side or underside of the vertical tract or on the underside of the usual vertical track pivot block. The transformer leads can be built into the vertical track or may have the claims the novel features of construction and novel combinations of parts, for which protection is desired.

In said drawings:

FIG. 1 is a front perspective view of a drafting board or machine in which the vertical track is equipped with my novel attachments.

FIG. 2 is an exploded view of one form of attachment, detached.

FIG. 3 is an enlarged transverse sectional view through the attachments shown in FIG. 2, when assembled for use.

FIG. 4 is a plan view of a modified form of attachment to the vertical track of the drafting board or machine.

As shown in FIGS. 1-3, inclusive, the drafting board (1) illustrates a machine comprised of a horizontal track 2, and with a vertical track 3 in the usual manner, the vertical track 3 being hinged at its upper end to the horizontal track 2 and normally overlying the drafting board 1 adjacent the left hand side thereof, as shown in FIG. 1.

Vertically slidably mounted on the underside of the vertical track 3 is a movable protractor support plate 4, the lower end of the plate 4 being outturned as at 4a, FIG. 1, and carrying the customary protractor head 5 carrying vertical and horizontal scales S and S. The upper end of the protractor support plate 4 is bent upwardly as at 41; to overlie the outer side of the vertical track 3, and further bent horizontally as at 40 to overlie the top surface of the vertical track 3, as shown in FIGS. 1 and 2. The upper edge of the portion 40 carries an extension 4d which is narrowed, as shown, and extends axially in spaced parallel relation to the top of the vertical track 3 for a substantial distance, as shown in FIGS. 1 and 2, and is provided with a longitudinal slot 4e, for the purpose hereinafter described. If desired, the upper end of the extension 4d may be provided with a small support wheel or the like (not shown) to maintain the spaced relation between the member 4d and the vertical track 3.

Adjustably mounted on the extension 4d in way of the slot 4e is a lamp 6 having a lateral extension 6a at its upper end provided with a perforation 6b, FIG. 2, receiving the lower end of a flexible conduit 7, FIG. 2, the lower end of which is threaded as at 7a (FIG. 2) and adapted to be passed through the perforation 6b in the extension 60, as shown more particularly in FIG. 3, lock nuts 8 and 9 being provided on the threaded portion 7a disposed above and below the extended portion 6a of lamp base 6 to securely anchor the lower end of the flexible conduit 7 to the lamp base 6, thereby maintaining said end of conduit 7 securely fixed in upright position to the extension 6a. The outer end of conduit 7 carries the usual reflector 10 for a lamp, now shown, which is carried in a suitable socket in the reflector, the electric wires for the socket being shown at 11 and 12, FIG. 3, which pass upwardly through the flexible conduit 7 and plate 6a to said socket in the reflector 10.

Means are provided for adjustably securing the lamp base 6 in vertically adjusted position with respect to the extension 4d, said means being shown more particularly in FIGS. 2 and 3. As shown, the lamp base 6 is provided adjacent the lower end with a hole 6c aligned with the slot 4e adapted to receive a knurled thumb screw 13 having a threaded shank 13a passing through the hole 6c and through the slot 4e and terminating below the underside of the extension 4d, as shown in- FIG. 3. Preferably Teflon washers 14 and 15, respectively, are provided around the screw shank 13a engaging the upper and lower faces of the extension 4d, as shown in FIG. 3.

Slidably mounted in the slot 4e below the extension 4d is a nut 16 receiving the threaded shank 13a of the knurled knob 13, said nut 16 having a reduced upper end 16a which may be circular or rectangular in shape to engage the side walls of the slot 43, the lower end of the nut being of larger diameter than the width of the slot 4e, as shown in FIG. 3, and engaging the Teflon washer on the lower side of the extension 4d, so that the knurled knob 13 is rotated the lamp base 6 may be loosened or tightened with respect to the slot 4e in extension 4d, thereby permitting the lamp base 6 to be adjusted longitudinally of the slot 42 and locked in desired fixed position to bring the lamp reflector 10 into relatively close proximity to the protractor head 5 in the act of drafting to properly illuminate the protractor head and to eliminate shadows from the vertical scale S.

In the modification shown in FIGS. 1 to 3, the wires 11 and 12 are shown as passed through a flexible cable 17, FIG. 1, leading to a transformer 18, FIG. 1, mounted on the top of the vertical track 3, as shown in FIG. 1, the transformer being supplied with suitable power leads from the source of electric power (not shown).

By the above construction, the transformer 18, the lamp base 6, the protractor support plate 4 and the protractor head 5 are all mounted on the vertical track 3 of the drafting machine so that as the protractor head 5 is moved horizontally and/or vertically, since the lamp 19 is attached to the same movable base plate 4 that supports the protractor head, the light will automatically remain in the same relative position with respect to the protractor 5 as well as to the protractor scales S,S', eliminating shadows completely. The lamp 10 can be positioned at any required distance from the protractor 5 and in any convenient location. Moreover, the lamp reflector 10 may have an On-Off switch conveniently located on the vertical track 3 on the lamp base 6, or on the lamp shade 10, which switch may be a three-position Off-Low-High switch.

The neck 7 of the lamp may be a flexible conduit such as a goose-neck cable type, and it should be long enough to center the lamp bulb over the center line of the vertical scale S of the protractor head 5. The transformer 18 should be of the smallest physical dimensions and of the lightest weight available. It is mounted on the upper end of the vertical track 3, separated from the lamp 10, so that there is no excessive weight on the protractor head, thus eliminating the need for extra counterbalance weights or brake adjustments on the vertical track. The transformer may be mounted on the upper side of the track or to the right or left side or underside of the vertical track, or on the underside of the pivot block of the vertical track. The transformer leads can, if desired, be built into the vertical track or suitable external wiring may be used. The tracking device can be of any suitable size, lightweight and capable of 'supporting the lamp assembly and allowing the lamp to slide or glide in vertical motion. It may be manufactured in one piece with the protractor support plate located under the vertical track in manufacturing new machines. It may be manufactured as an extension tube attached to the existing support plate as a modification in kit form for older drafting machines now in use. The slotted portion 4e should be long enough to enable the lamp bulb to be positioned on the same vertical center line as the top of an 18-inch vertical scale S, for maximum efficiency.

In the modification shown in FIG. 4, an alternative design is shown in which a protractor tracking plate 19 is slidably mounted on the underside of the vertical track 3, and has a lateral extension which carries the protractor head 5. At the opposite side of the plate 19 is an extension 19b having its upper and lower edges flanged upwardly as at 19c beyond the adjacent side of the vertical track 3, said flanges 19c being perforated to receive the threaded end 20a of a protractor tracking rod 20 which is in the form of a round rod provided with a keyway 20b in its outer edge. The tracking rod 20 is secured to the flanged portion 19c by means of apposed nuts 21, FIG. 4, engaging opposite faces of the flanges 19c to securely position the tracking rod 20 in parallel relation with the outer edge of the vertical track 3 but spaced therefrom.

On the tracking rod 20 is a slide 22 surrounding the rod 20 and carrying a knurled screw 23, the inner end of which engages in the keyway 20b, whereby when the nut 23 is tightened the slide 22 will be locked in adjusted position on the rod 20. The slide 22 carries a swivel joint 22a (FIG. 4) for a lamp supported tube 24 which engages the swivel joint 22a of slide 22. The outer end-of the tube 24 carries a swivel joint 24a receiving a corresponding end of a second lamp support tube 25, as shown in FIG. 4, while the outer end of the tube 25 carries a swivel; joint 25a engaging a similar joint on the reflector 10 of the lamp. The wires for the lamp socket in the reflector 10 pass through the tubes 25,24 and pass through flexible conduit 26, as shown in FIG. 4, to the transformer 18 which is located at the top of the vertical track 3. Otherwise, the parts shown in FIG. 4 are similar to and operate similarly to those shown in FIGS. 1-3 with the exception that in FIG. 4 the neck of the lamp is a two-part tube with wires inside having three swivel or ball joints so that the lamp may be positioned to virtually any angle from the lamp base slide 22 and the two-part tube device should be long enough to center the bulb over the center line of the vertical scale S.

Fluorescent, two-tube fixtures, or incandescent fixtures without transformer can be used as the lamp; also a strip-type receptacle for the wiring can be used and mounted underneath the left'hand side of the vertical track 3, thus eliminating excess wire. Whicheverdesign is used, the added weight attached to the movable base plate 4 or 19 that carries the protractor head 5 and the lamp fixture should be kept at a minimum. If it is not, a counterbalance weight inside the vertical track will have to be increased and the vertical brake adjusted.

My drafting device can be modified so its use can be incorporated in standard type vertical) drafting machines. In such application, it is especially essential that added weight be kept to a minimum. The transformer 18 may be mounted on the counterbalance device or possibly some convenient location on the drafting board.

I claim:

1. In a drafting machine provided with a vertical; track laterally movable across said board; a protractor support plate vertically slidable mounted on the vertical track; a protractor head carrying vertical and horizontal scales mounted on the lower portion of the support plate; said support plate having a narrowed extension track disposed parallel with and spaced from the vertical track, said extension having a longitudinally disposed keyway therein; a lamp support base adjustably mounted on the extension track in way of the keyway; a swingable lamp support tube having one end fixedly mounted on the lamp base, said tube carrying at its other end a reflector for a lamp; and a transformer mounted on the vertical track and connected to a source of electrical power, said transformer having leads extending therefrom and through the lamp support tube to the said lamp, whereby the lamp may be fixedly adjusted into close proximity to the protractor head to always illuminate same while eliminating shad- OWS on the vertical scale as the protractor head is shifted vertically or horizontally across the drafting board.

2. In a machine as set forth in claim 1, said narrowed extension track comprising an extension strip disposed axially of and spaced from the top of the vertical track, said extension strip having an axially disposed slot therein forming said keyway; said lamp support base having a hole registering with said slot; a screw having a knurled knob and a threaded shank passing through the hole and slot; a nut engaging the shank below the extension track; said nut having a non-rotatable engagement with the slot; and plastic washers disposed around said shank engaging the upper and lower faces of the extension track respectively.

3. In a machine as set forth in claim 1, said narrowed extension track comprising a rod having one end anchored to the support plate, said rod being disposed at the side of the vertical track and extending parallel with and in spaced relation thereto; said rod having a longitudinal slot in the outer portion thereof forming said keyway; said lamp support base comprising a slide block on said rod; and a knurled set screw threaded into said block and engaging the said slot.

4. In a machine as set forth in claim 1, said lamp support tube comprising a flexible conduit having its inner end fixedly secured to the lamp support base and extending normal thereto.

5. In a machine as set forth in claim 1, said lamp support tube comprising an articulated tube in which the respective sections are connected together by swivel joints, the inner section being fixedly secured to the lamp support base and extending normal thereto. 

1. In a drafting machine provided with a vertical; track laterally movable across said board; a protractor support plate vertically slidable mounted on the vertical track; a protractor head carrying vertical and horizontal scales mounted on the lower portion of the support plate; said support plate having a narrowed extension track disposed parallel with and spaced from the vertical track, said extension having a longitudinally disposed keyway therein; a lamp support base adjustably mounted on the extension track in way of the keyway; a swingable lamp support tube having one end fixedly mounted on the lamp base, said tube carrying at its other end a reflector for a lamp; and a transformer mounted on the vertical track and connected to a source of electrical power, said transformer having leads extending therefrom and through the lamp support tube to the said lamp, whereby the lamp may be fixedly adjusted into close proximity to the protractor head to always illuminate same while eliminating shadows on the vertical scale as the protractor head is shifted vertically or horizontally across the drafting board.
 2. In a machine as set forth in claim 1, said narrowed extension track comprising an extension strip disposed axially of and spaced from the top of the vertical track, said extension strip having an axially disposed slot therein forming said keyway; said lamp support base having a hole registering with said slot; a screw having a knurled knob and a threaded shank passing through the hole and slot; a nut engaging the shank below the extension track; said nut having a non-rotatable engagement with the slot; and plastic washers disposed around said shank engaging the upper and lower faces of the extension track respectively.
 3. In a machine as set forth in claim 1, said narrowed extension track comprising a rod having one end anchored to the support plate, said rod being disposed at the side of the vertical track and extending parallel with and in spaced relation thereto; said rod having a longitudinal slot in the outer portion thereof forming said keyway; said lamp support base comprising a slide block on said rod; and a knurled set screw threaded into said block and engaging the said slot.
 4. In a machine as set forth in claim 1, said lamp support tube comprising a flexible conduit having its inner end fixedly secured to the lamp support base and extending normal thereto.
 5. In a machine as set forth in claim 1, said lamp support tube comprising an articulated tube in which the respective sections are connected together by swivel joints, the inner section being fixedly secured to the lamp support base and extending normal thereto. 